Population Biology And Evolution Of Clonal Organisms

Fascinated by the diversity of living organisms, humans have always been curious about its origin. Darwin was the first to provide the scholary and persuasive thesis for gradual evolution and speciation under natural selection. Although we now have much information on evolution, we still don't understand it in detail. Many questions still remain open due to the complexity and multiplicity of interacting factors. Several approaches mainly arising from population ecology and genetics are presented in this book in order to help understand genetic variation and evolution.

Clonal animals, that is those that are genetically identical, are of great importance in biology. The supposed evolutionary advantages of sexual versus asexual reproduction are one of the central paradoxes of current evolutionary theory. The evolved strategy of asexual reproduction includes a large number of diverse species in many different groups, for example aphids, guppies, planktonic rotifers and others.

This volume contains the papers presented at a symposium on popula tion biology sponsored by the Deutsche Forschungsgemeinschaft. It was . held at the guest house of the University of Ttibingen at Oberjoch on May 15-19, 1983. Prior to this conference a small group of European biologists had met in Berlin (June 1981) and Pavia (September 1982) to discuss re search problems on the borderline between population genetics and evolutionary ecology. From the contributions and discussions at these meetings it became evident that the unification of approaches to evolutionary problems in population genetics and evolutionary ecology has not yet been suc cessful and requires further efforts. It was the consensus that a larger symposium with international participation would be helpful to con front and discuss the different approaches to population biology in order to assess "where we are now" and "where we should be going. " As a result an organizational committee was formed (F. Christiansen, S. Jayakar, V. Loeschcke, W. Scharloo, and K. W6hrmann) to iden tify topics that seemed, at least to them, to be fruitful in tackling problems in population biology. Consequently, a number of colleagues were asked to participate in the meeting. We have divided this book into chapters corresponding to the eight topics chosen. The volume begins with the relation between genotype and phenotype and is followed by a chapter on quantitative genetics and selection in natural populations.

Spontaneous self-cloning or clonality is a widespread phenomenon in the plant kingdom, and has a wide array of ecological and evolutionary implications. This volume is the outcome of an international workshop on clonal plant biology aimed at illustrating current progress and recent developments in the scientific study of clonality in plants. The first section of this book includes a collection of original research articles which demonstrate the wide variety of approaches and scientific challenges linked to clonality in plants. The topics covered in this section include ecological and evolutionary implications of sexual versus asexual propagation, including life-history evolution and sex-ratio dynamics, the importance of internal resource transport and remobilization of storage products for the invasiveness and competitiveness of clonal plants, a survey of clonal growth forms in grassland communities, and studies on the interactions between clonal plants and animals and fungi. The approaches used range from experimental studies on a broad variety of systems to mathematical modeling of clonal growth and its consequences. The second part features discussion and review papers on a diverse array of subjects, ranging from developmental considerations of clonality, principles of selection and evolution in clonal plants, a survey of clonality in algae, to potential implications of clonality for plant mating, and beyond. This part of the volume aims at presenting novel ideas and hypotheses, and at summarizing existing knowledge in previously under-researched areas, thereby providing directions for future research initiatives. This book captures ongoing cutting-edge research in the field of clonal plant ecology and evolution. It is directed to anyone from the undergraduate to specialist level who is interested in the biology of the intriguing phenomenon of asexual propagation in plants.